Loud commentary and cell phone fumbling may be distracting, but new research from the Journal of Consumer Research suggests that the presence of other people may enhance our movie-watching experiences. Over the course of the film, movie-watchers influence one another and gradually synchronize their emotional responses. This mutual mimicry also affects each participant's evaluation of the overall experience - the more in sync we are with the people around us, the more we like the movie.

"When asked how much they had liked the film, participants reported higher ratings the more their assessments lined up with the other person," explain Suresh Ramanathan and Ann L. McGill (both of the University of Chicago). "By mimicking expressions, people catch each other's moods leading to a shared emotional experience. That feels good to people and they attribute that good feeling to the quality of the movie."

In a series of experiments, the researchers had participants watch a video clip. Some of the participants watched alone, some with other people whose expressions could not be seen due to the presence of a partition, and some with other people whose expressions could be seen. The participants had a joystick they used to indicate their feelings at each moment.

While assessments did not line up by second - people liked or disliked specific scenes in the film according to their own tastes - the researchers found that people watching a film together appeared to evaluate the film within the same broad mood, generally tracking up or generally tracking down. In another study, the researchers videotaped participants and found that synchrony of evaluations can be traced to glances at the other person during the film and adoption of the observed expressions.

The researchers explain: "Participants who looked at each other at the same time appeared to note whether the other person's face expressed the same or different emotion than their own. Perceived congruity of expressions caused participants to stick with their current emotional expression . . . Perceived incongruity, on the other hand, led to a dampening of subsequent expressions."

They continue: "Social effects described above were bi-directional suggesting that such influences were mutual rather than the result of a leader-follower pattern."

The researchers are the first to examine how a shared experience affects not just our immediate feelings, but also our overall impressions of the experience as a whole. The study is also the first to look at contagious emotions in a naturally developing relationship between two participants, differing from prior studies that used a planted person to express agreement or disagreement with the participant.